I recently bought this very nice Ball wristwatch from John Grennan. I have managed to remove the back cover and was hoping someone could help me identify the 21 jewel Swiss movement. It is manual wind, adjusted to 5 positions, and under the regulator spring are the letters "BXC" (maybe Bulova?) I would also be interested in knowing the approximate year of production. THANKS

I did more research on the BXC code and discovered is was for the Avia watch company. Their full name was Avia Degoumois & Cie, and they were located in Neuchatel, La Chaux de Fonds, Switzerland. They were known for providing high grade movements to Ball for the manufacture of Ball railroad grade wrist watches.

Look under the balance. It should be marked AS 1604B. (A. Schild 1604).

William, The BXC code is positive identification for the Avia Watch Co. I also researched that company and found information that they did, in fact, supply movements to Ball. It has been about a month since I did the research, but I also recall finding a non-Ball Avia that had the same plates as we see in this watch. Do you have some other type of info that would be contrary to this finding? I'm still trying to find out the time period...I'm guessing late 60's to early 70's. What do you think?

What is stamped on plate UNDER the balance wheel? The importer code on the balance cock does NOT denote the manufacturer.

William, I'll have to take the back cover off again and probably won't be able to get to it for a week or so. I'll report back again when I get it off.

William, this excerpt is from the Wikipedia history of Webb Ball: "His original jewelry business in Cleveland grew into the Ball Watch Company (currently headquartered in La Chaux-de-Fonds, Switzerland), which used other watch companies' movements, perfecting them and then reselling them. Ball Watch Company also ordered watches complete from other watch companies. Ball used movements from the top American manufacturers, Elgin, Hamilton, and Waltham, and switched to Swiss Avia movements as early as the 1940s in their wristwatches. The Waltham Watch Company complied immediately with the requirements of Ball's guidelines, later followed by Elgin National Watch Company and most of the other American manufacturers: Aurora, Hamilton, Hampden, E. Howard & Co., Illinois, Seth Thomas, later on joined by some Swiss watch manufacturers: Audemars Piguet, Gallet, Longines, Record Watch, Vacheron Constantin."
Attached photo is from a Ball Avia circa 1945. The odd looking top plate has a similar look to the top plate on my later movement.

William, the only marking I can see under the balance of my watch is "WI". The gilt "BXC" is on top of the balance cock. Attached is another Avia Ball wrist watch example. Once again, it is earlier than my watch which I expect is from the early 1970's.

I'll try to find a picture of AS 1604. If you google up AS 1604 in Google images there are photos there.

William, I think you are probably right. The attached photo of an AS 1604 is much closer in appearance than the Avia ebauche I posted pics of. I also found the following info on another watch forum: "I later learned (too late for the article, which was published in October 1972) that the Elgin grade 873 was an A. Schild cal. 1604B, 13-ligne, 21-jewel, center-seconds, seconds-setting, manual-wind movement, exactly the same movement that Ball used in their first Official RR Standard wristwatch. Still later, I was told by a railroad watch inspector that some railroads wouldn't approve the Ball RR wristwatch with the Swiss movement because it was available only from Ball, so Ball got Elgin to use it also! Like the story that the CPR wouldn't approve the Ball RR wristwatch because it was based on an ebauche movement, that story never made much sense to me, either, but take it FWIW as anecdotal. I do recall seeing it listed in some catalog as something like Elgin B.W. Raymond 21-jewel wrist chronometer. It was years ago, and I don't recall the exact wording, but I do remember the use of the word "chronometer" and the B.W. Raymond, and of course the fact that it was a wristwatch. The catalog was from some time in the '60s."

William, I have found proof-positive that you are 100% correct!!! I went to my database to correct the identification of the movement...as I was typing the 1604 I noticed that the serial number I had logged in when I bought the watch was 16049. I thought, "wow, maybe that wasn't a serial number I was looking at on the movement." I immediately opened up the watch again and checked the number under a 10X loupe....what I thought was a "9" was actually a "B". IT WAS RIGHT THERE ALL THE TIME In gilt lettering on the top plate (you may be able to see it) it said "Model No. 1604B." Thank you so much for helping me nail this down

Just found another reference to the Ball 1604 movement. On page 229 of the "Gold Book" by Ehrhardt & Meggers they give definitive information on each model of Ball RR-approved wrist watches. I didn't think I would find anything in this book because its primary focus is pocket watches, but they do cover the Ball wrist watches.